This program is directed toward gaining a better understanding of, and improving delivery of service in several important areas of blood service delivery. These relate directly to the care of heart disease and cancer patients while undergoing surgical and medical treatment. One major focus of research is on human blood platelets, and is concerned with reducing the incidence of unpredictable failures of transfused platelets to exert their expected beneficial effects on transfusion. A second major focus is on immunological aspects of blood cell transfusion; these studies will significantly increase the ability to select donors to match patients, and to improve selection of unrelated donors for bone marrow transplantation. The overall objectives of the program are to accelerate the rate at which blood services are made available to patients; to investigate platelet physiology and develop new methods for separation, characterization and preservation of platelets; to study the immunology and immunogenetics of blood component transfusion and transplantation; and to develop new plasma derivatives needed for these patients. The program is comprised of four projects in cell biology, physiology, immunology and genetics. Through linkage with the largest Red Cross blood program, enormous resources are available for research, as well as opportunities for rapid transfer of knowledge. In one aspect of the study, genetic markers of the major histocompatibility complex (HLA and complement systems) will be studied in a large number of families. A central management structure and a policy board are included to move the program forward as expeditiously as possible toward the program goals. This program combines an unusual set of investigative abilities in a concerted attack upon important problems of the national blood resource. The program includes a special thrust toward the development and application of findings as rapidly as possible in routine practice.